Current limiting simulation of magneto-biased superconducting fault current limiter (SFCL) applied in 66kV/10kV power substation in China

The short-circuit fault currents in the large capacity transmission lines pose a challenge to the stability and safety of power system. Magneto-biased superconducting fault current limiter (MBSFCL) is with the advantages of two-stage current limiting, self-triggering and fast recovery so that it can effectively reduce the short-circuit fault current when applied to the urban power system. This paper analyzes the operation principle of MBSFCL and establishes a package type magneto-thermal coupled simulation model of MBSFCL based on MATLAB/SIMULINK. A power system model of a 66 kV/10 kV Zhang Tai Zi power substation which is in Liaoning province in China has been established and the grid-connected simulation applied MBSFCL has been achieved. Moreover, the grid-connected test is carried out, and the results of fault current, quench resistance and temperature change are obtained. The comparison of results between simulation and test verifies the accuracy of the simulation model and the application feasibility of MBSFCL

An efficient and secure itinerary-based data aggregation algorithm for WSNs

The existing privacy-preserving data aggregation methods in wireless sensor networks (WSNs) generally rely on a network infrastructure, and data privacy is achieved by encryption techniques. However, such an infrastructure is very susceptible to the dynamic network topologies, and excessive encryption process causes a high energy consumption and re-duces the accuracy of the aggregation results. In this paper, we propose a secure and concentric-circle itinerary-based data aggregation algorithm (called SCIDA for short). With the help of a well-designed itinerary for aggregation propagation and data aggregation, SCIDA is not susceptible to network topology structure and thus suitable for wireless sensor net-works with dynamic network topologies and can save energy for network infrastructure maintenance. In addition, SCIDA uses a secure channel to ensure data privacy and avoids dramatic energy consumption caused by heavy encryption operations. SCIDA does not need to carry out encryption during data aggregation, which significantly reduces energy consumption, and prolongs the lifetime of the network. Theoretical analysis and experimental results show that SCIDA enjoys low communication overhead and energy con-sumption, yet high safety and accuracy

Manufacture and Test of ITER 10-kA HTSCL Prototypes

To carry current for the ITER correction coils, the 10-kA high-temperature superconducting current leads studied here are designed. Current leads provide the transition from 4.5-K low temperature to room temperature. This paper summarizes the major design features of the prototypes, which is followed by a discussion of the manufacturing and testing. The test results approved their excellent performance on low joint resistance and long loss-of-flow accident time. The overheating time, mass flow, and heat loads to 5-K ends also reached the expectation

Manufacture and Test of the ITER TF Type HTS Current Lead Prototypes

High temperature superconducting current leads (HTS-CL) are designed to supply the current to the large superconducting ITER magnets for the operation with reduced heat load to the cryogenic system. The Toroidal field (TF) current leads are the largest with a current capacity of 68 kA each. The Institute of Plasma Physics of the Chinese Academy of Sciences (ASIPP) is responsible for the supply of the current leads based on a design jointly developed with the ITER organization. Before the supply of the TF HTS-CL series, a pair of prototypes was manufactured in 2014 by ASIPP and associated manufacturers according to previously qualified manufacturing procedures. Rigorous quality control measures were developed and applied in preparation for series manufacturing. To verify compliance of the prototypes with the ITER specification, thorough testing was conducted in 2015. The test items under particular scrutiny were: the pressure drop in the counter-flow heat exchanger, the loss of flow accident test after steady state operation at 68 kA current, the so-called overheating time of the HTS module following an induced quench, the electrical resistances of the soldered joints inside the lead assembly (i.e., the low temperature superconducting (LTS) to busbar and the HTS to LTS joints), and the conduction heat load per lead to the 4.5 K end. In this paper, the main manufacturing steps are discussed, and test results are presented and discussed